Question

Cells that use anaerobic respiration to acquire useful energy are most likely cells that lack...

Answer 1

I suppose it depends on what kind of anaerobic bacterium we're talking about, facilitative anaerobes or obligative anaerobes.

E. coli would be an example of a facilatative anaerobe. This bacterium grows well when there's plenty of nutrients around in the presence of oxygen, but it's also possible to grow the bacterium anaerobically. For example, if E. coli is grown without oxygen and using glucose as a carbon source, then the bacterium is going to generate some reducing power as NADH, energy in the form of ATP, and CO2 as a waste product, and acetate as a waste product.

I think the question you're answering is why can't anaerobic bacteria, specifically obligative anaerobes, grow in the presence of oxygen? Keep in mind that using oxygen as a terminal electron acceptor generates oxygen radicals that can cause extensive damage to the bacteria if it has no way to detoxify it, to the point where the bacteria would die in the presence of oxygen. There are several ways oxygen can become a reactive oxygen species such as hydrogen peroxide, oxygen radicals, and hydroxy radicals, including aerobic respiration.

So, what an obligative anaerobe is lacking is a way to detoxify reactive oxygen species that might form spontaneously in the presence of oxygen. Enzymes that might accomplish this are hyperoxy dismutases and peroxidases.

Answer 2

E. coli would only be able to grow anaerobically so forth it can get rid of side product from the regeneration of NAD... Depending on your terminology you can say doing anaerobic respiration does not mean you simply use another oxidant instead of oxygen.

Answer 3

Sorry also noticed I misunderstood the question.

Answer 4

Thank you both very much for the responses, I have a better understanding of the question now :D